World Premiere, 25 November 2017, Manchester

photo: Ian Phillips-McLaren

Two years ago I interviewed Arlene Sierra for this blog, ahead of a BBC Proms concert featuring her Butterflies Remember a Mountain. It is inspired by the annual mass migration of monarch butterflies from Canada to Mexico: each delicate insect making its infinitesimal contribution to the shimmering swarm; an unchanging annual cycle millions of years old; the sheer unimaginability of the scale of the endeavour, and a mysterious kink in the migration route are the source material for an intricate piece for piano trio.

Premiered on Saturday, Sierra’s Nature Symphony is another example of her fascination with the natural world and the first of its three movements draws directly from the earlier work. Set in a fast 5/4 time the rhythmic drive of the earlier trio is maintained, while continually reusing and developing its material, and using the larger forces of the orchestra to introduce minute detailing into the texture. This gives a sense of a stream (of migrating butterflies) moving inexorably forward, but in such a swarm that the whole presents an image in stasis, until suddenly they are at their destination, the Butterfly Mountain that gives the movement its name.

There is a satisfying symmetry in the overall shape of Nature Symphony: the third movement, Bee Rebellion, matches the first in rhythmic energy, and is in a similar tempo, but in 3/4 time seems busier. The pulse is destabilised by an insistent but irregular undertow of plucked double basses, while the violins and winds share a dialogue comprising short phrases that develop imperceptibly through the movement.​ Likening the life of the hive with elements of game theory - another favourite influence - Sierra creates a sense of frenetic but ultimately fruitless activity, and the movement ends with a sudden percussive crescendo and silence, a reminder of the colony collapse that bees are increasingly prone to, perhaps.

In the middle is a movement, titled The Black Place (after O'Keeffe), that is contrastingly song-like, with a long, slow melody shaped by fragments passed between horn, cor anglais and piccolo, and on through the orchestra, accompanied by long, held notes in the low strings. The rhythmic element is again there, but as a quiet, irregular pulse of plucked strings, harp and marimba, later taken up by piano, timpani and low brass. Inspired by Georgia O'Keeffe's paintings of the austere landscapes of New Mexico, the sharing out of these rhythmic, melodic and harmonic ingredients leads to a musical landscape whose tints, rather than colours, are constantly shifting.

"a personal sense of urgency"

This middle movement is a reminder of the composer’s concern at the fragility of nature: O'Keeffe's 'Black Place' - the Bisti Badlands - is under threat from fracking. The movement borrows melodic figures from Sierra's own 2008 setting of Hearing Things, a passionately environmentalist poem by Catherine Carter. In a recent interview Arlene Sierra told Rhinegold’s Katy Wright ‘I don’t see how anyone living today can fail to realise the urgency of what is going on with the natural world and what we human beings are doing to change things. I have a little boy now, who’s five, and I’m so conscious of how different the environment is from when I was a child. It’s a personal sense of urgency.’

Nature Symphony was performed by the BBC Philharmonic Orchestra at Manchester's Bridgewater Hall, conducted by Ludovic Morlot. The concert, which includes Bartók's 1st Piano Concerto and Dvořák's 8th Symphony, will be broadcast on BBC Radio 3 at 7.30pm on 1 December.